--- a/devtools/client/framework/test/browser_source_map-01.js
+++ b/devtools/client/framework/test/browser_source_map-01.js
@@ -1,43 +1,32 @@
 /* Any copyright is dedicated to the Public Domain.
  http://creativecommons.org/publicdomain/zero/1.0/ */
 
-// Whitelisting this test.
-// As part of bug 1077403, the leaking uncaught rejections should be fixed.
-thisTestLeaksUncaughtRejectionsAndShouldBeFixed("[object Object]");
-thisTestLeaksUncaughtRejectionsAndShouldBeFixed(
-  "TypeError: this.transport is null");
+"use strict";
 
 /**
  * Tests the SourceMapService updates generated sources when source maps
  * are subsequently found. Also checks when no column is provided, and
  * when tagging an already source mapped location initially.
  */
 
-// Force the old debugger UI since it's directly used (see Bug 1301705)
-Services.prefs.setBoolPref("devtools.debugger.new-debugger-frontend", false);
-registerCleanupFunction(function* () {
-  Services.prefs.clearUserPref("devtools.debugger.new-debugger-frontend");
-});
-
-const DEBUGGER_ROOT = "http://example.com/browser/devtools/client/debugger/test/mochitest/";
 // Empty page
-const PAGE_URL = `${DEBUGGER_ROOT}doc_empty-tab-01.html`;
+const PAGE_URL = `${URL_ROOT}doc_empty-tab-01.html`;
 const JS_URL = `${URL_ROOT}code_binary_search.js`;
 const COFFEE_URL = `${URL_ROOT}code_binary_search.coffee`;
 
 add_task(function* () {
   const toolbox = yield openNewTabAndToolbox(PAGE_URL, "jsdebugger");
   const service = toolbox.sourceMapURLService;
 
   // Inject JS script
-  let sourceShown = waitForSourceShown(toolbox.getCurrentPanel(), "code_binary_search");
+  let sourceSeen = waitForSourceLoad(toolbox, JS_URL);
   yield createScript(JS_URL);
-  yield sourceShown;
+  yield sourceSeen;
 
   let loc1 = { url: JS_URL, line: 6 };
   let newLoc1 = yield service.originalPositionFor(loc1.url, loc1.line);
   checkLoc1(loc1, newLoc1);
 
   let loc2 = { url: JS_URL, line: 8, column: 3 };
   let newLoc2 = yield service.originalPositionFor(loc2.url, loc2.line, loc2.column);
   checkLoc2(loc2, newLoc2);
@@ -59,38 +48,8 @@ function checkLoc1(oldLoc, newLoc) {
 function checkLoc2(oldLoc, newLoc) {
   is(oldLoc.line, 8, "Correct line for JS:8:3");
   is(oldLoc.column, 3, "Correct column for JS:8:3");
   is(oldLoc.url, JS_URL, "Correct url for JS:8:3");
   is(newLoc.line, 6, "Correct line for JS:8:3 -> COFFEE");
   is(newLoc.column, 10, "Correct column for JS:8:3 -> COFFEE");
   is(newLoc.sourceUrl, COFFEE_URL, "Correct url for JS:8:3 -> COFFEE");
 }
-
-function createScript(url) {
-  info(`Creating script: ${url}`);
-  let mm = getFrameScript();
-  let command = `
-    let script = document.createElement("script");
-    script.setAttribute("src", "${url}");
-    document.body.appendChild(script);
-    null;
-  `;
-  return evalInDebuggee(mm, command);
-}
-
-function waitForSourceShown(debuggerPanel, url) {
-  let { panelWin } = debuggerPanel;
-  let deferred = defer();
-
-  info(`Waiting for source ${url} to be shown in the debugger...`);
-  panelWin.on(panelWin.EVENTS.SOURCE_SHOWN, function onSourceShown(_, source) {
-
-    let sourceUrl = source.url || source.generatedUrl;
-    if (sourceUrl.includes(url)) {
-      panelWin.off(panelWin.EVENTS.SOURCE_SHOWN, onSourceShown);
-      info(`Source shown for ${url}`);
-      deferred.resolve(source);
-    }
-  });
-
-  return deferred.promise;
-}

--- a/devtools/client/framework/test/head.js
+++ b/devtools/client/framework/test/head.js
@@ -141,8 +141,50 @@ function checkHostType(toolbox, hostType
   let pref = Services.prefs.getCharPref("devtools.toolbox.host");
   is(pref, hostType, "host pref is " + hostType);
 
   if (previousHostType) {
     is(Services.prefs.getCharPref("devtools.toolbox.previousHost"),
       previousHostType, "The previous host is correct");
   }
 }
+
+/**
+ * Create a new <script> referencing URL.  Return a promise that
+ * resolves when this has happened
+ * @param {String} url
+ *        the url
+ * @return {Promise} a promise that resolves when the element has been created
+ */
+function createScript(url) {
+  info(`Creating script: ${url}`);
+  let mm = getFrameScript();
+  let command = `
+    let script = document.createElement("script");
+    script.setAttribute("src", "${url}");
+    document.body.appendChild(script);
+    null;
+  `;
+  return evalInDebuggee(mm, command);
+}
+
+/**
+ * Wait for the toolbox to notice that a given source is loaded
+ * @param {Toolbox} toolbox
+ * @param {String} url
+ *        the url to wait for
+ * @return {Promise} a promise that is resolved when the source is loaded
+ */
+function waitForSourceLoad(toolbox, url) {
+  info(`Waiting for source ${url} to be available...`);
+  return new Promise(resolve => {
+    let target = toolbox.target;
+
+    function sourceHandler(_, sourceEvent) {
+      if (sourceEvent && sourceEvent.source && sourceEvent.source.url === url) {
+        resolve();
+        target.off("source-updated", sourceHandler);
+      }
+    }
+
+    target.on("source-updated", sourceHandler);
+  });
+}